Mounting arrangement for collapsible steering column

ABSTRACT

A mounting arrangement for a collapsible steering column assembly having a lower portion adapted for rigid anchorage on a vehicle body and an upper portion adapted for axial collapse relative to the lower portion, the mounting arrangement including a bracket on the upper column portion having an open ended slot therein, a plurality of land surfaces on the bracket adjacent each longitudinally extending edge of the slot imparting to the edges progressively increasing thickness from the open end of the slot, a capsule adapted for rigid connection to the vehicle body and for sliding reception in the slot, and a plurality of integral resilient fingers struck from the body of the capsule and adapted to grippingly engage respective ones of the land surfaces on the bracket, the fingers generally simultaneously releasing the land surfaces upon initial collapse of the upper column portion.

United States Patent 1 Milton et al.

1451 July 24,1973

[ MOUNTING ARRANGEMENT FOR COLLAPSIBLE STEERING COLUMN [75] Inventors:Thomas J. Milton, Bay City; John W.

Skelly, Saginaw, both of Mich.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

22 Filed: May 15, 1972 [21] Appl. No.: 253,401

12/1972 Bennett 74/492 Primary EQEtlfltiileT- MiitOll Kau frnan Att0rneyWarren E. Finken, Saul Schwartz et a1.

[57] ABSTRACT A mounting arrangement for a collapsible steering columnassembly having a lower portion adapted for rigid anchorage on a vehiclebody and an upper portion adapted for axial collapse relative to thelower portion, the mounting arrangement including a bracket on the uppercolumn portion having an open ended slot therein, a plurality of landsurfaces on the bracket adjacent each longitudinally extending edge ofthe slot imparting to the edges progressively increasing thickness fromthe open end of the slot, a capsule adapted for rigid connection to thevehicle body and for sliding reception in the slot, and a plurality ofintegral resilient fingers struck from the body of the capsule andadapted to grippingly engage respective ones of the land surfaces on thebracket, the fingers generally simultaneously releasing the landsurfaces upon initial collapse of the upper column portion.

MOUNTING ARRANGEMENT FOR COLLAPSIBLE STEERING COLUMN This inventionrelates generally to collapsible steering column assemblies forautomobile type vehicles and more particularly to a mounting arrangementfor such column assemblies.

Collapsible steering column assemblies are currently widely used in theautomotive industry and typically include a first or lower portionanchored to the vehicle body and a second or upper portion connected tothe lower portion and adapted for axial collapse relative to the latterin an energy absorbing mode. Typically the second column portion has abracket thereon which is releasably attached to the vehicle body throughmounting capsules which are bolted to the body and connected to thebracket through frangible connections such as plastic pins injectionmolded into both the bracket and the capsule. Consequently, wheneverthere is relative movement between the upper column portion and thevehicle body the frangible connection is destroyed and an entire newbracket must be installed. A mounting arrangement according to thisinvention incorporates reusable mounting capsules which obviatereplacement of the entire bracket and which also facilitate rapid andsubstantially unimpeded separation of the bracket upon initiation ofcollapse of the column assembly.

The primary feature, then, of this invention is that it provides a newand improved mounting arrangement for a collapsible steering columnassembly in an automobile type vehicle. Another feature of thisinvention is that it provides a new and improved mounting arrangementwherein reusable connecting means, disposed between a portion of thecolumn assembly and the vehicle body, resiliently grip the columnassembly and are calibrated to effect release thereof underpredetermined axial loading on the column assembly. Still anotherfeature of this invention resides in the provision in the mountingarrangement of a bracket on the collapsible portion of the columnassembly having thereon a plurality of land portions defining agenerally tapering configuration, the land portions being adapted to begripped by resilient finger means rigidly attached to the vehicle bodyand the tapering configuration assuring that upon substantiallysimultaneous separation of the land portions from the finger means thelatter will not engage any of the other land portions so that collapseof the column assembly is substantially unimpeded. A still furtherfeature of this invention resides in the provision of reusableconnecting means in the form of a capsule including a flat body sectionadapted for rigid attachment to the vehicle body and a plurality ofintegral resilient fingers struck from a pair of opposite side edges ofthe body section, the fingers being vertically spaced to form generallylongitudinally tapering channels adapted to slidably and releasablyreceive corresponding land portions adjacent the side edges of a slot onthe steering column assembly. These and other features of this inventionwill be readily apparent from the following specification and from thedrawings wherein:

FIG. 1 is a fragmentary partially broken away side elevational view ofan automobile type vehicle body having a collapsible steering columnassembly supported thereon through a mounting arrangement according tothis invention;

FIG. 2 is an enlarged sectional view taken generally along the planeindicated by lines 2-2 in FIG. 1;

FIG. 3 is an enlarged sectional view taken generally along the planeindicated by lines 3-3 in FIG. 1;

FIG. 4 is an enlarged sectional view taken generally along the planeindicated by lines 4-4 in FIG. 3;

FIG. 5 is an enlarged view of a portion of FIG. 4 but showing only aportion of the steering column mounting bracket;

FIG. 6 is an enlarged side elevational view of the mounting capsuleportion of a mounting arrangement according to this invention; and

FIG. 7 is an enlarged perspective view of the mounting capsule.

Referring now to FIG. 1 of the drawings, there shown is a fragmentarypartially broken away view of the forward portion of an automobilevehicle body designated generally 10 including interiorly thereof arigid fire wall 12 separating the engine compartment of the vehicle fromthe passenger compartment. The fire wall 12 includes an aperture 14through which projects the lower portion of a collapsible steeringcolumn assembly 16. The steering column assembly 16 is generallyconventional and includes a lower portion 18 adapted for rigid anchorageon the fire wall 12 through a plate assembly 20 bolted to the fire wall.The steering column assembly further includes an upper portion 22connected to the lower column portion 18 through a corrugated metalsection 24. The corrugatedsection 24 normally maintains the upper columnportion 22 in rigid relation to the lower column portion 18. In theevent of a substantial axially directed impact on the upper columnportion the corrugated section 24 is adapted for plastic deformationwhich effects energy absorption and permits axial collapse of the uppercolumn portion 22 rela' tive to the lower column portion 18. Rearwardlyof the tire wall 12 there is disposed transversely across the passengercompartment an instrument panel structure designated generally 26 andforward of the instrument panel structure there is disposed a rigidbracket assembly 28 adapted as described hereinafter for cooperationwith a mounting arrangement according to this invention in releasablysupporting the upper column portion 22 on the vehicle body.

As seen best in FIG. 3, the upper column portion 22 includes acylindrical mast jacket 30 connected at its lower end to the corrugatedsection 24 and at its upper end to a hub 32. A cylindrical shift tube 36is rotatably disposed within the mast jacket 30 for manual manipulationin a conventional manner by a shift lever and shift bowl assembly, notshown, rotatably disposed on the hub 32. A steering shaft 38 isrotatably disposed within the shift tube 36 and is. connected at itsupper end to a steering wheel 39 disposed outboard of the hub 32 and atits lower end forward of the tire wall 12 to the vehicle steering gear,not shown.

Referring now to FIGS. 1, 2 and 3, the mast jacket 30 has rigidlyattached thereto an instrument panel bracket 40 adapted as describedhereinafter for releasable connection to the bracket assembly 28 on thevehicle body. The instrument panel bracket 40 is generally U-shaped inconfiguration and includes a main body portion 42 embracing and rigidlyattached to the mast jacket 30 and a pair of laterally spaced outwardlyextending wing flanges 44. Each wing flange has formed therein agenerally rectangular slot 46 opening rearwardly with respect to thedirection of axial collapse of the upper column portion 22. Each slotincludes a pair of parallel side edges 48 extending generally axially ofthe steering column assembly. The instrument panel bracket 40 is locatedaxially along the mast jacket 30 such that in an uncollapsed conditionof the steering column assembly, FIGS. 1 and 2, the instrument panelbracket is disposed in juxtaposition with a flange portion 50 of thebracket assembly 28.

The bracket assembly 28 further includes a pair of laterally spaced andgenerally vertically oriented rods 52 which are rigidly attached to thevehicle body forward of the instrument panel structure 26 and whichproject downwardly through appropriate apertures in the flange portion50 of the bracket assembly, each of the rods having a threaded portion54 extending beyond the lower surface of the flange portion 50, FIG.

.2 and 3.

Those skilled in the art will recognize, of course, that axial collapseof the upper column portion 22 effects forward movement, FIG. 1, of theinstrument panel bracket 40 relative to the flange portion 50 on thebracket assembly 28. Accordingly, provision is made for releasablyconnecting the instrument panel bracket to the bracket assembly 28. Moreparticularly, and with reference to FIGS. 2, 3, and 7, the slots 46 havedisposed therein respective ones of a pair of identical mountingcapsules 56 preferably fabricated as metal stampings. Describing onlyone of the capsules, the latter includes a generally flat body section58 having an aperture 60 therein, a pair of integral upper resilientfingers 62 and 64, and a trio of integral lower resilient fingers 66, 68and 70 struck from one side thereof. It will be understood, of course,that a similar plurality of resilient fingers are struck from theopposite side of the body section and function in the same manner as thefingers recited hereinbefore. Each of the resilient fingers 62, 64, 66,68 and 70 includes a bearing surface 62, 64, 66', 68' and 70', thesurfaces 62' and 64' opposing the surfaces 66', 68' and 70 to definegenerally a channel extending along the side of the body section.

As seen best in FIG. 6, when the upper and lower fingers on the mountingcapsule are unstressed each assumes a predetermined position relative tothe others. More particularly, in the unstressed condition the hearingSurfaces 62 and 64' are aligned in a common plane. The bearing surfaces66', 68 and 70', however, are aligned in three separate planes spacedprogressively further apart from the plane of the bearing surfaces 62'and 6.4. in particular, the bearing surface 70' is spaced from the planeof the bearing surfaces 62' and 64 by a distance designated X in FIG. 6.Similarly, the bearing surfaces 68' and 66 are spaced from the plane ofbearing surfaces 62' and 64', respectively, by distances Y and Z, FIG.6. The distance Z exceeds the distance Y and the distance Y, in turn,exceeds the distance X so that the upper and lower fingers along theside of the body section 58 define a longitudinally extending channelhaving resilient side walls which exhibit a longitudinal taper withrespect to the vertical height of the channel.

Referring particularly now to FIGS. 4 and 5, each wing flange 44 on theinstrument panel bracket 40 has formed thereon adjacent the side edges48 of the slots 46 a plurality of land surfaces corresponding to theupper and the lower fingers on the mounting capsules 56. Moreparticularly, and describing only one side edge since the land surfacesadjacent each are identical, on the upper surface of the wing flangeadjacent the edge 48 of the slot 46 there is formed a pair of upper landsurfaces 72 and 73 disposed in a common plane. On the lower surface ofthe wing flange 44 adjacent the edge 48 of the slot 46 there is formed atrio of land surfaces 74, 76 and 78 disposed in separate planes atvarying distances from the plane of land surfaces 72 and 73. As seenbest in FIG. 5, the land surface 74 is spaced from the plane of the landsurfaces 72 and 73 by a distance X while the land surfaces 76 and 78 arespaced from the plane of land surfaces 72 and 73 by, respectively, thedistances Y and Z. The distance Z exceeds the distance Y and thedistance Y, in turn, exceeds the distance X. Accordingly, the upper andlower land surfaces along the edge 48 of the slot 46 impart a thicknessconfiguration to the edge tapering longitudinally from a thinnestportion adjacent the open end of the slot to a thickest portion adjacentthe closed end of the slot.

As seen best in FIGS. 2, 3 and 4, the tapering channel formed by theupper and lower fingers on the mounting capsule slidably receives theside edge 48 of the slot 46 with the bearing surfaces 62' and 64' on theupper fingers engaging the land surfaces 73 and 72, respectively, andthe bearing surfaces 66', 68 and engaging, respectively, the landsurfaces 78, 76 and 74. The distance Z corresponds generally to thedistance Z but is slightly larger than the latter so that as themounting capsule is inserted into the slot 46 the lower finger 66 andthe upper finger 62 are resiliently flexed, the forces generated therebycausing friction between the land surfaces and the bearing surfaceswhich friction effects retention of the capsule in the slot in the wingflange. Similarly, the distances Y and x' correspond to but slightlyexceed, respectively, the distances Y and X so that both the lowerfingers 68 and 70 also experience slight resilient flexure thereby togenerate further friction between the bearing surfaces and land surfacesfor retention of the capsule. The force required to slide the mountingcapsule out of the slot 46 is a direct function of the resilience or theamount of flexure of the upper and lower fingers on the mountingcapsule. Accordingly, the force required for such seaparation may bequite accurately predicted or varied depending upon the distances X, Yand Z or the distances X, Y and Z.

With the mounting capsules 56 inserted in the slots 46 in the instrumentpanel bracket 40 as described hereinbefore, the apertures 60 in themounting capsules register. with and receive therethrough the threadedportions 54 of the rods 52, FIG. 3. Each mountingcapsule is then rigidlyand permanently connected to the bracket assembly 28 by respective onesof a pair of nuts 80 received on the threaded portions 54 of the rods52. Accordingly, the upper column portion 22 is thereby rigidly butreleasably attached to the bracket assembly 28.

Describing now a typical steering column collapse sequence, the criticaldimensions of the corrugated metal section 24 of the steering columnassembly ensure that the axial force necessary to initiate collapse ofthe upper column portion 22 exceeds the force required to slide themounting capsules 56 out of the slots 46 in the instrument panelbracket. Accordingly, when an axial force of magnitude sufficient toinitiate collapse of the upper column portion 22 is exerted on thesteering column assembly, the upper column portion moves leftwardly,FIG. 1, toward the lower column portion 18. Simultaneously, theinstrument panel bracket 40 moves leftwardly, FIG. 2, with respect tothe mounting capsules 56 since the latter are rigidly attached to thebracket assembly 28 through the rods 52 and the nuts 80. After slightrelative movement between the instrument panel bracket and the mountingcapsules, the upper fingers 62 and 64 and the lower fingers 66, 68 and70 generally simultaneously slide off of the land surfaces 73, 72, 78,76 and 74, respectively. Thus, after only slight relative movementbetween the instrument panel bracket and the mounting capsules,

the frictional forces originally retaining the latter in the formercease so that collapse of the upper column portion is not frictionallyretarded.

Referring to FIGS. 5 and 6, the distance Z exceeds the distance Z inorder to effect flexure of the upper and lower fingers 62 and 66. Thedistance Z, however, exceeds the distance Y to ensure that as thecapsule separates from the instrument panel bracket through the open endof slot 46, the finger 66 will pass easily over the land surface 76without generating any significant retarding friction. Similarly, thedistance Y exceeds the distance X' to ensure that the finger 68 willpass easily over the land surface 74 without generating any significantretarding friction. Thus, after the initial friction retention forcescease, no further retarding friction is developed between the mountingcapsules and the instrument panel bracket.

Having thus described the invention, what is claimed 1. In a mountingarrangement for a collapsible steering column assembly a first portionof which is fixed on a vehicle body and a second portion of which isadapted for axial collapse relative to said first portion, thecombination comprising, bracket means rigidly attached to said secondportion and defining an edge portion extending generally longitudinallyof said steering column assembly, means on said bracket means generallyadjacent said edge portion defining a plurality of land surfacesimparting to said edge portion progressively increasing thickness in thedirection of collapse of said steering column assembly, a rigid anchormeans on said vehicle body, and resilient finger means on said anchormeans grippingly engaging respective ones of said land surfaces in anuncollapsed condition of said steering column assembly thereby tosupport said second portion on said vehicle body and further adapted toseparate generally simultaneously from each of said land surfaces underpredetermined axial loading on said second portion without thereaftergrippingly engaging any other of said land surfaces thereby to permitsubstantially unimpeded separation between said bracket means and saidanchor means during collapse of said steering column assembly.

2. In a mounting arrangement for a collapsible steering column assemblya first portion of which is fixed on a vehicle body and a second portionof which is adapted for axial collapse relative to said first portion,the combination comprising, bracket means rigidly attached to saidsecond portion and having therein a slot opening rcarwardly with respectto the direction of collapse of said steering column assembly anddefining a pair of laterally spaced side edges extending generallylongitudinally of said steering column assembly, means on said bracketmeans generally adjacent each of said side edges defining a plurality ofaxially spaced land surfaces, said land surfaces imparting to each ofsaid edges progressively increasing thickness from the open end of saidslot to the closed end thereof, a rigid anchor means on said vehiclebody reclined in said slot in an uncollapsed condition of said steeringcolumn assembly, and resilient finger means on said anchor meansgrippingly engaging respective ones of said land surfaces in theuncollapsed condition of said steering column assembly thereby tosupport said second portion on said vehicle body and to retain saidanchor means in said slot and further adapted to separate generallysimultaneously from each of said land surfaces under predetermined axialloading on said second portion without thereafter grippingly engagingany other of said land surfaces thereby to permit substantiallyunimpeded separation between said bracket means and said anchor meansduring collapse of said steering column assembly.

3. In a mounting arrangement for a collapsible steering column assemblya first portion of which is fixed on a vehicle body and a second portionof which is adapted for axial collapse relative to said first portion,the combination comprising, bracket means rigidly attached to saidsecond portion and having therein a slot opening rearward with respectto the direction of collapse of said steering column assembly anddefining a pair of laterally spaced side edges extending generallylongitudinally of said steering column assembly, means on said bracketmeans generally adjacent each of said side edges defining a plurality ofaxially spaced land surfaces, said land surfaces imparting to each ofsaid edges progressively increasing thickness from the open end of saidslot to the closed end thereof, a mounting capsule adapted for insertionin said slot through the open end of the latter, means rigidly affixingsaid mounting capsule to said vehicle body in a manner whereby saidcapsule is disposed in said slot in an uncollapsed condition of saidsteering column assembly, and means on said capsule defining a pluralityof integral resilient fingers grippingly engaging respective ones ofsaid land surfaces in the uncollapsed condition of said steering columnassembly thereby to support said second portion on said vehicle body andto retain said capsule in said slot and further adapted to separategenerally simultaneously from each of said land surfaces underpredetermined axial loading on said second portion without thereaftergrippingly engaging any other of said land surfaces thereby to permitsubstantially unimpeded separation between said bracket means and saidcapsule during collapse of said steering column assembly.

4. In a collapsible steering column assembly mounting arrangementincluding a steering column assembly having a first portion adapted forfixed anchorage on a vehicle body and a second portion adapted for axialcollapse relative to said first portion and further including rigidbracket means on said second portion, a mounting capsule adapted toreleasably connect said bracket means and a rigid portion of saidvehicle body comprising, a body portion having means therein adapted tofacilitate rigid attachment of said body portion to said vehicle body,and a plurality of resilient finger portions for gripping said bracketmeans integral with said body portion and extending transversely of thelatter in vertically spaced relation to define a pair of channelsextending in parallel relation along a pair of opposite edges of saidbody portion, said resilient finger portions in a relaxed conditionthereof being spaced vertically progressively further apart from one endof said body portion to the other thereby to impart to each of saidchannels generally a longitudinal tapering configuration.

5. In a collapsible steering column assembly mounting arrangementincluding a steering column assembly having a first portion adapted forfixed anchorage on a vehicle body and a second portion adapted for axialcollapse relative to said first portion and further including rigidbracket means on said second portion, a mounting capsule adapted toreleasably connect said bracket means and a rigid portion of saidvehicle body comprising, a generally flat body portion having meansthereon adapted to facilitate rigid attachment of said body portion tosaid vehicle body, and a plurality of integral resilient finger portionsfor gripping said bracket means struck from said body portion along apair of opposite edges of the latter, alternate ones of said fingerportions along each of said edges being disposed in vertically spacedrelation thereby to-define a pair of channels extending in parallelrelation along said edges, the vertical spacing between said fingerportions progressively increasing from one end of said body portion tothe other thereby to impart to each of said channels generally alongitudinal tapering configuration.

1. In a mounting arrangement for a collapsible steering column assemblya first portion of which is fixed on a vehicle body and a second portionof which is adapted for axial collapse relative to said first portion,the combination comprising, bracket means rigidly attached to saidsecond portion and defining an edge portion extending generallylongitudinally of said steering column assembly, means on said bracketmeans generally adjacent said edge portion defining a plurality of landsurfaces imparting to said edge portion progressively increasingthickness in the direction of collapse of said steering column assembly,a rigid anchor means on said vehicle body, and resilient finger means onsaid anchor means grippingly engaging respective ones of said landsurfaces in an uncollapsed condition of said steering column assemblythereby to support said second portion on said vehicle body and furtheradapted to separate generally simultaneously from each of said landsurfaces under predetermined axial loading on said second portionwithout thereafter grippingly engaging any other of said land surfacesthereby to permit substantially unimpeded separation between saidbracket means and said anchor means during collapse of said steeringcolumn assembly.
 2. In a mounting arrangement for a collapsible steeringcolumn assembly a first portion of which is fixed on a vehicle body anda second portion of which is adapted for axial collapse relative to saidfirst portion, the combination comprising, bracket means rigidlyattached to said second portion and having therein a slot openingrearwardly with respect to the direction of collapse of said steeringcolumn assembly and defining a pair of laterally spaced side edgesextending generally longitudinally of said steering column assembly,means on said bracket means generally adjacent each of said side edgesdefining a plurality of axially spaced land surfaces, said land surfacesimparting to each of said edges progressively increasing thickness fromthe open end of said slot to the closed end thereof, a rigid anchormeans on said vehicle body reclined in said slot in an uncollapsedcondition of said steering column assembly, and resilient finger meanson said anchor means grippingly engaging respective ones of said landsurfaces in the uncollapsed condition of said steering column assemblythereby to support said second portion on said vehicle body and toretain said anchor means in said slot and further adapted to separategenerally simultaneously from each of said land surfaces underpredetermined axial loading on said second portion without thereaftergrippingly engaging any other of said land surfaces thereby to permitsubstantially unimpeded separation between said bracket mEans and saidanchor means during collapse of said steering column assembly.
 3. In amounting arrangement for a collapsible steering column assembly a firstportion of which is fixed on a vehicle body and a second portion ofwhich is adapted for axial collapse relative to said first portion, thecombination comprising, bracket means rigidly attached to said secondportion and having therein a slot opening rearward with respect to thedirection of collapse of said steering column assembly and defining apair of laterally spaced side edges extending generally longitudinallyof said steering column assembly, means on said bracket means generallyadjacent each of said side edges defining a plurality of axially spacedland surfaces, said land surfaces imparting to each of said edgesprogressively increasing thickness from the open end of said slot to theclosed end thereof, a mounting capsule adapted for insertion in saidslot through the open end of the latter, means rigidly affixing saidmounting capsule to said vehicle body in a manner whereby said capsuleis disposed in said slot in an uncollapsed condition of said steeringcolumn assembly, and means on said capsule defining a plurality ofintegral resilient fingers grippingly engaging respective ones of saidland surfaces in the uncollapsed condition of said steering columnassembly thereby to support said second portion on said vehicle body andto retain said capsule in said slot and further adapted to separategenerally simultaneously from each of said land surfaces underpredetermined axial loading on said second portion without thereaftergrippingly engaging any other of said land surfaces thereby to permitsubstantially unimpeded separation between said bracket means and saidcapsule during collapse of said steering column assembly.
 4. In acollapsible steering column assembly mounting arrangement including asteering column assembly having a first portion adapted for fixedanchorage on a vehicle body and a second portion adapted for axialcollapse relative to said first portion and further including rigidbracket means on said second portion, a mounting capsule adapted toreleasably connect said bracket means and a rigid portion of saidvehicle body comprising, a body portion having means therein adapted tofacilitate rigid attachment of said body portion to said vehicle body,and a plurality of resilient finger portions for gripping said bracketmeans integral with said body portion and extending transversely of thelatter in vertically spaced relation to define a pair of channelsextending in parallel relation along a pair of opposite edges of saidbody portion, said resilient finger portions in a relaxed conditionthereof being spaced vertically progressively further apart from one endof said body portion to the other thereby to impart to each of saidchannels generally a longitudinal tapering configuration.
 5. In acollapsible steering column assembly mounting arrangement including asteering column assembly having a first portion adapted for fixedanchorage on a vehicle body and a second portion adapted for axialcollapse relative to said first portion and further including rigidbracket means on said second portion, a mounting capsule adapted toreleasably connect said bracket means and a rigid portion of saidvehicle body comprising, a generally flat body portion having meansthereon adapted to facilitate rigid attachment of said body portion tosaid vehicle body, and a plurality of integral resilient finger portionsfor gripping said bracket means struck from said body portion along apair of opposite edges of the latter, alternate ones of said fingerportions along each of said edges being disposed in vertically spacedrelation thereby to define a pair of channels extending in parallelrelation along said edges, the vertical spacing between said fingerportions progressively increasing from one end of said body portion tothe other thereby to impart to each of said channels generally alongitudinal tapering configuration.